Combination fluid-pressure lock.



PATENTED APR. 18, 1905.

W. J. HOFSTATTER. GOMBINATIQN FLUID PRESSURE LOCK.-

3 SHEETS-SHEET 1.

APPLICATION FILED MAY 31, 1904.

INVENTOR.

WITNEEEES: WW Y PATENTBD APR. 18,1905.

W. L HOPSTATTER. COMBINATION FLUID PRESSURE LOCK.

APPLICATION FILED MAY 31, 1904.

s SHEETSSHEET 2.

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No. 787,575. PATENTED APR. 18, 1905.

W. J. HOFSTATTER.

' COMBINATION FLUID PRESSURE LOOK.

APPLICATION FILED MAY 31, 1904.

INVENTOR.

WITNESSES:-

Patented April 18, 1905.

WILLIAM J. HOFSTATTER, OF TOLEDO, OHIO.

COMBINATION FLUID-PRESSURE LOCK.

SPECIFICATION forming part of Letters Patent No. 787,575, dated April 18, 1905. [application filed May 31, 1904. Serial No. 210,384.

To all whmn it may concern:

Be it known that LWILLIAM J. HOFSTATTER, a citizen of the United States, residing at T- ledo, Lucas county, Ohio, have in vented a new and useful Improvement in a Combination Fluid-Pressure Lock, of which the following is a specification.

My invention relates to a combination fluidpressure lock, and has for its object to provide a lock of the kind that is adapted to readily secure a closure which when locked thereby requires to unlock it the application to the lock in a predetermined order of a series of distinct fluid-pressures in which each succeeding pressure of the series differs in the number of its pressure units from the next preceding pressure and in which each pressure of the series in order to be operative must closely approximatea certain measured number of pressure units arbitrarily selected as one of the numbers of the combination; moreover, that is readily adjustable to be operated by other and different combinations of arbitrarily-selected pressures applied in a definite order.

A further object is to provide a safe and efficient lock of the kind wherein the parts of the locking and unlockingmechanism after being operated to unlock a'closure may be readily returned to their normal positions for locking it again.

A further object is to provide a lock of the kind that is adapted to be connected into and operated by either air or liquid pressure systems.

I accomplish these objects by the novel construction, combination, and cooperation of parts, as hereinafter described, and illustrated in the drawings, in which- Figure l is a side elevation of my lock. Fig. 2 is a top plan view .of the same; Fig. 3, a side elevation in which the right-hand pressure-cylinder is shown in section on line X X of Fig. 2. Fig. 4 is a section of a pressure-cylinder on line X X of Fig. 2. Fig. 5

is a horizontal section of a pressure-cylinder on line Y Y of Fig. 3. Fig-6 is a top plan' view of the lock-casing with stufling-boxes, inlet-valve, and shift-bars; and Fig. 7 is a horizontal cross-section of inlet-valve, showing inlet closed and vent open.

- The lock is illustratedin Fig. 1 of the drawings as connected with the main air-pipe A of a train air-brake system by a connectingpipe 1, suitable to the location of the lock, and in Fig. 3 as adapted to lock the sliding door B of a freight-car of the train.

The lock comprises a suitable casing 2, which incloses the combination pressure unlocking mechanism, (and which may be located atany point convenient for access,) and the casing 3, which contains the automatic locking and unlocking mechanism,only operatively accessible for unlocking through the combination unlocking mechanism in casing 2, the casing 3 being preferably located in the door-jamb in a position suitable to receive a bolt 4, projected from the edge of the door to be locked, and is connected with the combination unlocking mechanism in the casing 2 by the pipe 5.

The unlocking mechanism inclosed in casing 2 comprises a series of cylinders 6,6", and 6 the lower ends of which are respectively secured in the annular sockets 7, 7", and 7*, formed integral with a common cored base 8, provided with the main conduit 9, having the end enlargements 10 and 11, the by-pass 12, extending between and connecting cylinders 6 and 6, the by-pass 13, extending between and connecting cylinders 6 and 6, the by-pass 14, extending between and connecting cylinder 6- and the enlargement 11 of the conduit 9, the vertical bore 15, central through the base of socket 7 and intersecting the enlargement 10 of the conduit 9, the bores 15 and 15 respectively, central through the bases of sockets 7 and 7 b and intersecting the by-passes 12 and 13, respectively, the conduits 16 and 17, intersecting conduit 9 and having the enlarged upper portions 16 and 17, respectively intersecting the by-passes 12 and 13, and the bypass 18, extending from the bore 15 through the base of socket 7, beneath the wall of cylinder 6, and the by-passes 18 and 18, having like relation to cylinders 6 and 6 respectively. The base 8 is also provided with the standards 19, one adjacent to and in front of each cylinder and alined in the same vertical plane. Each cylinder of the series is provided with a piston 20, having a rod 21 extending upward axial to the cylinder, and near the top each cylinder is provided with the ears 22, projecting radially inward from the inner wall of the cylinder at diametric opposite points. The ears are perforated and threaded to receive the pressure-adjusting stud-bolts 23, which at their lower ends are made conical to enter countersunk orifices 24, in line therewith in diametric projections from an annular disk 25 of suitable diameter, which rests upon the top of a helical spring 26 of suitable resistance, that is concentric around the rod 21 and resting on the piston 20. By running the studbolts down in the ears the spring is compressed and adjusted to the required resistance to the upward movement of the piston. Each cylinder has formed longitudinally thereof in its outer wall in a plane of its axis that is preferably at right angles to an axial plane through the stud-bolts 23 the diametrically opposite slide-grooves 27, in which are movably mounted the slides 28, which at their top ends are secured to an annular plate 29, having a diameter adapting it to rest on the top end of the cylinder and a central opening adapting the plate to pass below the level of the tops of the stud-bolts. The top of the plate is provided with the diametric arch 30, central of which in line with the piston-rod 21 is provided an orifice 31 to receive the upper end portion of the rod, which is threaded to receive the outer and inner lock-nuts 32, by which the rod is secured to the arch. The depths of the grooves 27 are so adjusted that the outer faces of the slides 28 are flush with the periphery of the cylinder to the circle of which they conform. The grooves extend to near the top of the sockets in which the cylinders are mounted, and the slides are of a length to rest on the bottom ends of the grooves when the annular plate 29 is resting on top of the cylinder. The lower end portions of the slides are angled outward to form the hooks 33. Each cylinder is provided with a movable sleeve 34 of about one-half its height, which is fitted to move smoothly and closely around and upwardly and downwardly on the cylinder. Above the sleeve 34 each cylinder is provided with the helical spring 35, which engages the top edge of the sleeve and is confined on the cylinder by a detachable ring 36, suitably secured to the periphery of the cylinder flush with its top end. The spring 35 is adapted to yieldingly hold the lower edge of the sleeve in engagement with the hooks 33 of the slides. Each sleeve is provided centrally of its length with the semi-annular boss 37 which is cored to form the by-pass 38, terminating at the intersecting ports 39, formed in the inner face of the sleeve at diametric opposite points. The ports 39 are adapted when the sleeve is raised to the proper height 1 line with above its normal position and then turned a fixed distance to be brought into register with the ports 40, formed in the outer wall of each cylinder. The ports 40 intersect vertical extensions of the by-passes 12 13 14 and 18, 18, and 18 through the walls of the respective cylinders, and,when each port 39 is in register with a port 40 there is formed a contiuuous by-pass from the bore 15 (which connects" cylinder 6 with the main conduit 9) through all the cylinders in succession back to the enlargement 11 of the conduit 9.

On a level with the ports 40 of the cylinders there is provided on one side of the cylinders a shift-bar 41 and on the opposite side the shift-bar 42. These shift-bars are mounted in the guide-bearings 43 in the cross-bar 44, supported by the standard 45, secured to the rear end of the base 8, and the front end of the bars project through the stufling-boxes 46 in the front end of the casing 2.

The front end of the shift-bar 41 is provided with a handle-bar 47, by which it is pulled forward, and to the rear portion of the bar is connected a spring 48, which returns the bar to its normal position after being pulled forward by the handle and released;

The shift-bar 42 is provided at its front end with the yoke 49, by which it is shifted backward and forward, as hereinafter described.

Opposite each cylinder each shift-bar is pro vided with a horizontal slot 50, which extends through the sides of the bar, and in each slot is pivotally mounted a pawl 51, which is projected inward and forward at an acute angle to the bar by a plate-spring 52, secured to the outer side of the bar in position to press on a flattened portion of the pawl opposite the pivot, the spring being thereby adapted to yieldingly hold the pawl in the position described.

The sleeves are each provided with the shoulder-lugs 53 and 53', which are located oppositely, as shown in Fig. 2, with their rear faces in diametric alinement and extending from the base of the boss 37, prolonged around the sleeves a suitable distance above the boss. To each sleeve there is suitably connected one end of a helical spring 53", the other end of which is connected rearward to the next rearward standard, as shown in Fig. 1.

At the end of the boss 37 nearest the standard 19 each sleeve is also provided with a lockinglug 54, having its outer face serrated to engage the serrated inner face of the standard, which is in position for such engagement when the sleeve is raised from its normal position a suitable distance and turned in the direction to move the lug 54 toward the standard, and the inner face of the standard is serrated for a distance that permits the engagement of the lug 54 at different elevations of the sleeve.

The ports 40 of the cylinders are nearly in sides of the standards 19 that are nearest the shift-bar 41 and are located about midway of the height of the cylinders, and by raising or lowering the sleeves until the ports 39 are in the horizontal plane of the ports 40 and then turning the sleeves in the direction to move the lugs 54 into engagement with the standards the ports 39 and 40 will be brought into register, and the sleeves will be locked by the lugs 54 in such position.

Each sleeve is provided with a pair of incuts 54, which are located diametrically opposite each other and extend from its lower edge upward a suitable distance, each incut having a width to allow free passage of the hooks 33 of the slides, and the incuts are so located with reference to the locking-lug 54 that when the latter is in engagement with its standard 19 each incut will be opposite one of the slides in position to allow free upward and downward movement of the slides by the piston without the hooks coming into engagement with the sleeve.

The enlarged bore 11 of the conduit 9 is internally threaded, and at the inner end portion of the bore forward of the intersection of the by-pass 14 there is provided a checkvalve 55, normally held closed by a spring 56, adapted to yield to open the valve when the pressure in the pipe (which is coupled into the outer portion of the bore 11) is greater than the pressure in the conduit.

The enlargements 16 and 17 of the cond uits 16 and 17 are each also internally threaded and below the intersection of the by-passes 12 and 13, respectively, are provided with the spring-pressed check-valves 57, normally held closed by the springs 58, but which yield to open the valves when the pressure in the bypasses 12 and 13 is greater than the pressure in the conduit 9. The top ends of the enlargements are provided with the closure-plugs 16 and 17".

The enlarged end bore of the conduit 9 is also internally threaded, and one end of the connecting-pipe 1 is coupled therein. The connecting-pipe 1 is provided with the plugvalve 59, which is coupled into the pipe 1 below the yoke 49 of the shift-bar 42. The stem of the valve extends upward and is provided at the top with a handle-lever 60, having a short arm portion 61 extending opposite to the handle from the stem, and the arm 61 is provided with the pin 62, extending upward between the arms of the yoke 49. The plug of the valve is provided with a diametric bore 63, which extends through the plug in the vertical plane of the handle and is located to register with the pipe 1 when the handle is turned parallel therewith and to close the pipe 1 in the direction of the pipe A and open a vent 64 from the conduit 9 when the handle is in the position shown in Figs. 2 and 6. hen in the latter position, the pin 62 is in engagement with the outer arm 65 of the yoke and the shift-bar 42 is at the limit of its forward movement. When the handle of the valve is pulled around forward into alinement with pipe 1 to open the'valve, the pin 62 engages the inner arm 66 of the yoke and shifts the bar 42 to the limit of its rearward movement.

The casing 3 isa cylindrical shell, closed at the top, and its bore 66 has the diameter of its central portion increased and provided with a side opening 67 through a thickened portion of the wall of the shell to receive the bolt 4 of a door B. The bolt 4 is provided with the incline 68 on the upper side of its free end, and adjacent to the incline the bolt is also provided with the vertical slot 69. In the bore of the cylinder is a piston-bolt 7 0, comprising the guide-disk 71, having the axial stem 72 projecting above the disk, the piston 7 3 and the flattened bolt 74 connecting the piston and the disk and centrally incut to form the upwardly -extending catch 75, and the downwardly-extending catch 76 having its free end portion'beveled inwardto form the incline 77. The piston-bolt thus formed is inserted into the lower end of the casing, with a helical spring 78 mounted on the stem of the disk, the whole being of a length to require some compression of the spring by the reducercoupling 79, threaded on the lower end of the casing, in order to fully introduce the piston 73 into the lower end of the bore 66. The pipe 5 being then coupled thereto, it is manifest that when the parts described are in the position locking the bolt 4, as shown in Fig. 3, any pressure in pipe 5 suflicient to overcome the resistance of the spring 78 will move the piston upward until the stem engages the top of the casing and the catch 7 6. is moved out of the slot 69, in which position the bolt 4 is released and the door may be opened. When the pressure in pipe 5 is reduced to normal, the bolt 7 O returns to its normal position, in which position it operates as a spring-bolt adapted to be forced upward by the incline 68 of the door-bolt 4 engaging the incline 77 as the bolt 4 is pushed inward through the side opening 67 until the catch 76 is forced into the slot 69.

The lock thus constructed may be adjusted ,to be opened by a certain combination of fluidpressures, each having a different number of units of pressure, by so adjusting the resistance of the spring 26 of each cylinder that when the piston has raised the sleeve of its cylinder the distance required to bring the ports 39 on a level with the ports 40 the resistance of the spring will exactly equal the number of pressure units arbitrarily selected to operate that cylinder.

Assuming that the lock is located on a freight-car and connected to the main air-pipe of the air-brake system of a freight-train, with the parts in normal position, as shown in Figs. 1 and 2,-and in position locking the door of the car, as shown in Fig. 3, and assuming that the springs 26 of the cylinders are adjusted in the order of 6, 6, and 6" at a resistance at port-level of the sleeves of sixty, forty-five, and fifty-five pounds gage-pressure, respectively, and assuming that the train-pipe A is carrying a normal working pressure of seventy pounds, the operation of unlocking the car-door is as follows: The engineer in the cab having the combination signals to an operator at the car to open the valve 59, the operator then pulls the handles of the valve forward parallel with the pipe 1, and by this operation the valve is opened, thereby raising the pressure in conduits 9, 15, and 18 to that of the train-pipe and shifting the bar 42 to the limit of its rearward movement. The pressure on the piston of cylinder 6 being seventy pounds raises the piston, and with it the sleeve of the cylinder, a distance that brings the ports 39 of the sleeve above the level of the ports 40 of the cylinder and the shoulder-lug 53 of the sleeve in the path of the movement of the adjacent pawl 51 of the bar 41; After opening the valve the operator at the car signals the engineer that the valve is open. The engineer thereupon reduces the pressure in the train-pipe A until the gage shows a pressure of sixty pounds and then signals the operator, who then pulls the shift-bar 41 and releases it, which completes the first operation. In this operation by the reduction of the train-pipe pressure to sixty pounds the piston and the sleeve are lowered by the springs 26 and 35 until the ports 39 of the sleeve are on a level with the ports 40 of the cylinder, and the shoulder-lug 53 of the sleeve being (at such elevation of the sleeve) still within the path of movement of the adjacent pawl 51 of the shift-bar 41 when the operator pulled the shift-bar 41 the pawl 51 was brought into engagement with the lug 53, thereby turning the sleeve and bringing the locking-lug 54 into locking engagement with the standard 19 and the ports 39 into register with the ports 40, and thereby established a continuous bypass from conduit 15 to cylinder 6, through bypass 18 and its extension, the bypass 38 of the sleeve of the cylinder 6, and the bypass 12 and its extension in cylinder 6, and a pressure of sixty pounds was applied.

to the piston of 6 by the first operation,which operated in like manner as described for cylinder 6 in raising the ports 39 of the sleeve of cylinder 6 above the level of the ports 40 and also bringing the lug 53 of that sleeve in the path of the adjacent pawl 51 of the shiftbar 41. At a second signal of the operator at the car after the first operation is completed by pulling the shift-bar 41 and releasing it the engineer makes a further reduction of the pressure in train-pipe A to a gage-pressure of forty-five pounds, which causes alike. reduction of pressure in the conduit 9 and also in the cylinders 6 and 6 through their connections with conduit 9, the check-valve 57, conleases it.

trolling conduit 16, operating to assist in the speedy equalization of pressure of those cylinders with that of conduit 9. This further reduction of pressure causes the pistons of cylinders 6 and 6 to descend for a distance. The sleeve of cylinder 6 being locked to its standard 19 remains stationary, while the sleeve of cylinder 6 descends with the piston of that cylinder until the ports 39 of the sleeve are on the level of the ports 40 of the cylinder. At a signal of the engineer after this second reduction the operator at the car again pulls the shift-bar 41 forward and re- By this second operation of the bar the pawl 51, opposite cylinder 6, engages the shoulder-lug 53 of the sleeve of that cylinder and turns the sleeve until the locking-lug 54 of the sleeve is in looking engagement with its standard 19 and the ports 39 are in register with ports 40 of that cylinder. The sleeves of both cylinders 6 and 6 are unaffected by this second shift of the bar, because the lug 53 of the sleeve of cylinder 6 has already been moved. out of the path of travel of its engaging pawl 51, and the sleeve or cylinder 6 being still in its normal position its engaging pawl 51 passes above its shoulder-lug 53. By this second operation of the shift-bar 41 the bypass from conduit 9 is further extended by the bypass 38 and bypass 13 and its extension in the cylinder 6 to the cylinder 6", and the pie ton of cylinder 6 is raised, and with it the sleeve of the cylinder, a distance; but by reason of the spring 26 of that cylinder being adjusted to a resistance of fifty pounds when the ports 39 of the sleeve are on a level with the ports 40 of the cylinder and the pressure admitted to the cylinder being only forty-five pounds an increase of five pounds pressure is required to raised the ports 39 to the level of the ports 40. The engineer then raises the pressure in the train pipe until the gage marks fifty pounds and signals the operator, who then makes the third shift of the bar 41, whereby the pawl 51 opposite cylinder 6 engages the shoulder-lug 53 of the sleeve of that cylinder and turns the sleeve until its lug 54 is in locking engagement with its standard 19 and the ports 39 are brought into register with the ports 40, thereby extending the bypass from conduit 9 to the pipe 5, through the bypass 38 of the sleeve of cylinder 6, the bypass 14 and its extension in cylinder 6, and the enlargement 11 of the conduit 9 and establishing a pressure of fifty pounds on the piston of easing 3. If this pressure is equal to or greater than the known resistance of the spring 78, the door-bolt 4 will be released from the catch 76, and the unlocking operation will be completed. If, however, its known resistance is greater than fifty pounds, the engineer raises the gage-pressure in the train-pipe A until it equals or exceeds the re sistance of the spring 76.

It is apparent that the operative combination of pressures may be extended to include an arbitrary operative pressure for the mechanism of casing 3 by shortening the stem 7 2 and providing means (not shown) for regu lating the resistanceof the spring 78, such as are employed for thesprings of cylinders 6, 6, and 6. Thus provided and regulated, it is obvious that any less pressure than the fixed operative pressure on the piston 7 3 will not fully release the catch 76 and any greater pressure would move catch into the slot 69 of the bolt 4, and thereby prevent its being unlocked except by the exact degree of pressure for which the spring had been regulated.

When the door has been unlocked as described, all of the parts are returned to their normal positions, as shown in Figs. 1 and 2, by turning the handle of the plug-valve back into the position there shown, the forward movement of the shift-bar 42 produced thereby operating to bring all of the pawls 51 into engagement with the shoulder-lugs 53 (all of which had been moved rearward by the previous operations of the bar 41) and to simultaneously turn the sleeves of the cylinders in the direction to move the locking-lugs 54 out of engagement with the standards. IVhen so moved, the springs 35 move the sleeves clownward, and aided by the springs 53 they return to their normal positions. The valve 59 being closed in position to open the vent'64, the air compressed in the cylinders, lay-passes, and, conduits quickly escapes therefrom through the several check-valves and through the vent until normal atmospheric pressure is restored therein, the several pistons returning to their normal positions as the pressure on them diminishes. The handle of the valve is then turned slightly forward to close the vent, in which position the lock is protected from dust. It is manifest also that any failure to conduct the operation of unlocking in the exact order of the combination and to use substantially the gage-pressures established for the operation of the several cylinders will result in a failure to unlock, although such failure cannot be known until the whole operationof the combination is completed, a failure to register the ports 39 and 40 of any one cylinder rendering all further pressures ineffective, as they can produce no result except to raise and lower the pistons of the cylinders that have their sleeve and cylinder ports in register or which have their sleeves locked to the standards with the ports out of register, as would be the case if a wrong pressure is used for any cylinder. After any successful operation, however, all the parts that have been moved will be restored to their normal positions by closing the valve in the position shown in Fig. 2, so that after any unsuccessful operation of the combination the valve 59 must be closed and again opened be fore a new operation is begun.

While I have described the operation of my lock by means of a train-air-brake system, it is manifest that it may be connected into any similarly-controlled air or liquid systems de signed and used for the special purpose of operating locks. Its use is therefore not limited to incorporation with the air-brake system of freight-trains, although it is especially adapted for such purpose in the protection it aflords against the depredations of car thieves while cars are en route or standing on sidings or in freight-yards.

What I claim to be new is- 1. In a combination fluid-pressure lock, the combination with a door-bolt, of a lock adapted to receive the door-bolt, means in the lockbody adapted to automatically lock the doorbolt against withdrawal .from the lock-body, means for automatically unlocking the doorbolt and requiring for such unlocking the application to said unlocking means of a definite and predetermined degree of fluid-pressure, no less and no more, and means to apply different fluid-pressures to said unlocking means, equal to, greater, or less than the pressure required.

2. In a combination fluid-pressure lock, the combination with a door-bolt, of a lock-body adapted to receive the door-bolt, mechanical means in the lock-body adapted to automatically engage and lock the door-bolt against withdrawal from the lock-body, and adapted to be actuated by fluid-pressure to release the door-bolt, fluid-pressure means normally disconnected from the lock-body, for unlocking the locking means, means to automatically connect the fluid-pressuremeans with the lockbody, comprising a series of spring-pressed pistons, adjustable to different resistances and adjusted to require for such connection the application thereto, in order of succession, of a predetermined combination of known, definite, anddifferent fluid-pressures, and means to successively apply differential fluid-pressures to the pistons.

3. In a combination fluid-pressure lock, the combination with a door-bolt, of a lock-body' adapted to receive the door-bolt, mechanical means in the lock-body adapted to automatically engage and lock the door-bolt against withdrawal from the lock-body, and adapted to be actuated by fluid-pressure to release the door-bolt, fluid-pressure means, normally disconnected from the lock-body, for unlocking and adapted, when engaged, to connect them with the line, a series of spring-pressed pistons, one for each conduit-section, adapted to respectively engage and successively move their respective sections into engagement with the shift-bar, means to diflerently adjust the s iiring-pressure on the pistons, and means to successively apply different fluid-pressures to the pistons, and actuate them to move the sections successively into engagement with the shift-bar.

4. In a combination fluid-pressure lock,-the combination with a door-bolt, of a lock-body adapted to receive the door-bolt, means to automatically lock the door-bolt against withdrawal from the lock-body, means in the lockbody for unlocking the locking means, and requiring the application thereto of a known and definite fluid-pressure for such unlocking, no less and no more, fiuid-pressure means comprising a controllable fluid-pressure supply, a main conduit from the supply, and a sectional branch conduit adapted to connect the lockbody with the main conduit, said sectional conduit comprising stationary sections and a movable section normally disconnected from the stationary sections, means operated by fluid-pressure and manually-operated means for moving the movable section into line connection with the stationary sections, and requiring for the establishing of such connection the application to said fluidpressure-operated means of a predetermined fluid-pressure of not less or more than a fixed number of units of pressure.

5. In a combination fluid-pressure lock the combination with a door-bolt of a lock-body adapted to receive the door-bolt, a reciprocative lock-bolt in the lock-body adapted, in either direction of its movement, to automatically engage and lock the door-bolt against Withdrawal, and to release the door-bolt at a point intermediate of the extremes of its movement, a spring adapted to move the lockbolt in one direction into locking engagement with the door-bolt, said spring having a known resistance when the lock-bolt is at the releasing-point of its movement, a piston adapted to move the lock-bolt in the opposite direction, and means to apply ditferent fluid-pressures to the piston equal to, less, or greater than the known resistance of the spring at the releasing-point of the lock-bolt.

6. In a combination fluid-pressure lock the combination with a door-bolt of a lock-body adapted to receive the door-bolt, a reciprocative lock-bolt in the lock-body adapted, in either direction of its movement, to automatically engage and lock the door-bolt against withdrawal, and to release the door-bolt at a pointintermediate of the extremes ofits movement, a spring adapted to move the lock-bolt in one direction into locking engagement with the door-bolt, said spring having aknown resistance when the lock-bolt is at the releasing point of its movement, a piston adapted to move the lock-bolt in the opposite direction, means comprisingacontrollablefluid-pressure supply, and a sectional conduit adapted to connect the lock-body with the supply, said sectional conduit having one or more movable sections normally disconnected from the line of the conduitand disconnecting thelock-body from the fluid-pressure means, means to move the disconnected section or sections into line, comprising a cylinder for each disconnected section, a piston in each cylinder adapted to engage and move its section, a spring adjustably compressed on each piston to a predetermined resistance to the movement of the piston, and means to severally and successively apply different fluid-pressures to the pistons in their order of succession in the line, and to the piston of the lock-body.

7. In a combination fluid pressure lock, the combination with a door-bolt, of a lock-body adapted to receive the door-bolt, means to antomatically lock the door-bolt against withdrawal from thelock-body, means in thelockbody for unlocking the locking means, and requiring the application thereto of a known and definite fluid-pressure for such unlocking, no less and no more, fluid-pressure means comprising a controllable fluid-pressure supply, a main conduit from the supply, and asectional branch conduit adapted to connect the lockbody with the main conduit, said sectional conduit comprising disconnected stationary sections having end ports in common horizontal and vertical planes, movable sections between the stationary sections and having end ports adapted to register with the end ports of the stationary sections and form a continuous line, the ports of said movable sections being normally out of the common horizontal and vertical planes of the ports of the stationary sections and disconnected therefrom, fluid-pressure means to successivelylift 'the movable sections into the common horizontal plane of the ports of the stationary sections and other horizontal planes above and below said common horizontal plane, according as the pressure equals, or isless, or greater than a predetermined pressure, and means to shift the end ports of the movable sections in any one of the horizontal planes into the common vertical plane of the ports of the stationary sections and lock them in said plane, comprising a shift-bar, a pawl on the shift-bar foreach movable section, a lug on each movable section adapted to be carried by the section into the path of the opposite pawl, a lockingstandard for each movable section, and a locking-lug on each movable section, adapted to be moved into locking engagement with the standard by movement of the shift-bar.

IIO

supply and adapted to apply the pressure of the supply to the piston opposite to that of the spring; a by-pass from the conduit extending in the wall of the cylinder to a port in its outer wall; a port in the cylinder o,pposite the first port and a by-pass extending therefrom, connected or adapted to be connected to a fluid-pressure-controlled lock;- a sleeve movably mounted on the cylinder, normally closing the cylinder-ports; a by-pass in the wall of the sleeve having opposite ports adapted to be brought into register with the ports of the cylinder; means connected to the piston and engaging the sleeve, adapted to raise the sleeve according as the piston is raised, and to bring the ports of the sleeve on a level with the ports of the cylinder when the opposed pressures of the spring and the fluid are balanced at the predetermined distance of movement of the piston; a lockingstandard adjacent to the sleeve; a locking-lug on the sleeve, located to engage the standard when the sleeve is turned a distance, to bring the ports of the sleeve in register or vertical alinement with the ports of the cylinder; and manual means adapted to engage the sleeve when so raised, and turn the sleeve until the locking-lug is engaged with the standard.

9. In a combination fluid-pressure lock, the combination with a pressure-controlled fluidsupply conduit, and a pressure-controlled spring-lock, ofa series of cylinders, each having by-passes extending from opposite ports; a sleeve movably mounted on each cylinder and having a by-pass extending between opposite ports adapted to be brought into register with the ports of the cylinder, the bypasses of the cylinders and the sleeves when all are so connected being adapted to form a m continuous connection between the supplyconduit and the lock; connections from the by-passes to each cylinder; a piston in each cylinder adapted to be raised by the pressure of the fluid in the conduit; slide-hooks movthe sleeve of the cylinder, and adapted to yieldingly hold the sleeve lowered on the cylinder, with the ports of the sleeve below the level of the ports of the cylinder and out of vertical alinement therewith; a locking-standard adjacent to each sleeve; a locking-lug on each sleeve, normally disengaged from the standard and adapted to be brought into engagement therewith when the sleeve is turned in one direction; a manually-movable shiftbar, mounted in guide-bearings and extending at one side past each cylinder; shiftingpawls, extending inward and forward from the shift-bar, one opposite each cylinder; a shoulder on each sleeve, normally below the level of the shifting bar, when the sleeve is in its normal position, and adapted to be raised into position to be engaged by the adjacent pawl when the sleeve is raised, and cause the sleeve to be turned until the locking-lug is locked to the standard when the shift-bar is pulled forward a fixed distance; notches in the sleeves, normally out of line with the hook-slides, and adapted to be brought into line therewith when the sleeves are turned and locked to the standards; a manual valve adapt,

ed to open and close the conduit, and means connected to and operated in closing the valve, to release the pressure and return the several parts to their normal positions, substantially as set forth. In testimony whereof I have hereunto set my hand this 25th day of May, 1904.

WILLIAM J. HOFSTATTER. Witnesses:

WILLIAM H. MooR, LAURA S. YOUNGS. 

